pictures

There’s a very basic distinction in kinds of pictures (and therefore kinds of graphics) we use with computers. The difference is really simple, but very difficult to describe precisely. In fact, we don’t even have great words for the two categories. In the old days, they referred to the two types as “raster” and “vector”. I prefer “image-based” and “object-based”. Here’s a first attempt at the definitions: An image-based (or raster) graphic represents the pictures by measuring the color at a pre-determined set of locations (usually a grid). Read more…

When we talk about image-based graphics, we talk about it being a regular collection (usually a grid) of samples (or pixels). It’s time to be a little more precise about this. The term pixel is (I’m told) short for the term “picture element.” (Wikipedia, of course talks about this) Unfortunately, there is an ambiguity when we talk about a grid. And for reasons that we become clearer later, it is better to think about pixels one way rather than the other. Read more…